Various types of fluid material and media are employed for different purposes throughout commerce and industry. For example, there are various products in the areas of personal care, home care, air care, transportation care and food industries that require a fluid material to be dispensed in some manner from a source of such material. Further, when this material is sold in commerce, it must be contained and stored in some type of container while awaiting use. Ultimately, when that product is used, it must be dispensed from its storage container to the desired location for use.
In the prior art, there are many different types of dispensers that are employed for the delivery of a stored fluid material to its desired location for use. For example, a storage container having a flexible body with a nozzle tip extending therefrom is commonly provided for such a purpose. An example of such use can be seen in the context of a ketchup dispenser, where a user squeezes the container body to urge the fluid material (i.e., ketchup) out from container body and through the nozzle tip to accurately deposit the fluid material at the desired location. In such an application, the amount of fluid that is ultimately delivered is determined by how much the user actually squeezes the container body. While this method has provided marginally acceptable results, this method also typically yields an erratic fluid volume since more or less fluid material may be delivered on each successive squeeze of the container body. Also, the container must be held upright to avoid leakage because no valves are employed in the fluid nozzle tip.
In another example of a prior art dispensing device, a flexible container is provided that holds a volume of fluid material to be delivered. In an attempt to overcome the leakage issue noted above, a single one-way check valve is provided at the exit port of the flexible container. When the flexible body is squeezed, the material is urged out under pressure through the valve. The difficulty here is that the valve, over time, becomes partially clogged, thereby requiring that the user apply additional pressure to cause the valve to open. As a result, once the valve opens, the additional pressure causes more fluid material to be deposited than the user typically would have desired.
U.S. Pat. No. 7,419,322 represents a significant advancement over the above-described systems by providing a fluid dispensing device (10) that includes a container (20) with an interior fluid storage region (22) therein. A flexible metering housing (26) defined by a button (36) and a base plate (34) is disposed in fluid communication with the fluid storage region (22) with a first one-way valve (30) disposed between the container (20) and the flexible metering housing (26). One-way flow from the interior fluid storage region (22) of the container (20) fills the predetermined volume of the metering chamber (32) with fluid by vacuum action when the button (36) is depressed and then released. A second valve (40) is in fluid communication with the metering housing (26) and permits one-way fluid flow from the metering chamber (32) to the exterior outer region of the container (20) when the metering housing (26) is depressed again. Each time the metering housing (26) is depressed a substantially equal volume of fluid (24) is dispensed from the container (20).
U.S. Patent Application Publication No. 2008/0264973 relates to a similar concept, but discloses several additional embodiments that possess a simplified design as compared to those disclosed in U.S. Pat. No. 7,419,322, wherein the valving and dispensing functions are incorporated into a design that is relatively simplified and cost-effective to produce, yet that also provides excellent results. In particular, FIG. 17 and the corresponding description of U.S. Patent Publication No. 2008/0264973 discloses a “two-piece” configuration which has been found to provide particularly desirable results.
The present invention is essentially an improvement upon this “two-piece” configuration, which provides excellent results in certain situations and configurations of the metered dispensing pump.